This invention relates to pet litter containing water-activated adhesive material to bind the litter particles together when activated by liquid excreta from the pet. In particular, it relates to pet litter treated with liquid-activated adhesive material that forms clumps of good structural integrity to permit the affected material to be easily separated from litter material that has not been contaminated by pet excreta.
Many of the brands of pet litter now on the market have been treated to control odor, dust, and bacteria but not for the specific purpose of forming clumps that allow easy separation of the clumped material from the particular material that has not been in contact with the pet excreta.
When a pet deposits liquid excreta, normally urine, on a bed of untreated litter, the liquid progresses down through the particulate material and wets the particles as it comes to them. The litter is commonly said to absorb the liquid, although it may be more accurate to say that the liquid is adsorbed on the many surfaces of the particulate material. For the sake of simplicity in the following description, the words "sorption" and "sorbent", which cover both, will be used. The force of adhesion causes the wetted particles to cling together to some extent, but this force is not very strong and it substantially entirely disappears when the liquid evaporates. As a result, there is little or no clumping effect, and the only way to be certain of getting rid of litter that has been affected by the urine, is to dispose of the entire tray of litter. While this need not be done after every use by the pet, it is usually done by pet owners at least about once a week in order to avoid the build-up of obnoxious odors in the vicinity of the litter tray.
Even litter that has odor-controlling material in it, must be disposed of every few days. Since there is no way of separating litter that has come in contact with the pet urine from litter that has not, it is common to throw away the entire contents of the litter tray and to replace it with a new bed of litter. This means that a considerable quantity of litter will be used, and a recent study indicated that pet owners typically use about 15 kg of pet litter per month. Not only is there a constant expense involved in replacing litter so frequently, there is also a considerable problem of disposing of the used material, particularly by pet owners who live in apartments or who, for any reason, are unable to remove the used litter to an acceptable disposal location.